1. Field of the Disclosure
The disclosure relates to an optical component and a light source device, and particularly to an optical lens and a light source device using the optical lens.
2. Description of Related Art
In the recent years, along with the progression of semiconductor technology, light emitting diode (LED) is able to emit light beam having high luminous intensity, and the luminous efficiency of the LED is constantly improved. Compared to some conventional light sources, the LED light source has the advantages of energy efficient, small size and long life expectancy. Therefore, the conventional light sources are gradually replaced with the LED light source, and the LED light source is widely applied in the field of lighting, such as car headlights, street lamps, desk lamps, etc.
The LED light sources used for illumination generally has an angle of half maximum power that is approximately 120 degrees, and the luminous intensity of the LED at the forward direction substantially perpendicular to the light-emitting surface is higher while that at the oblique direction oblique to the forward direction is weaker. In other words, the light emitted by the LED has a Lambertian distribution. Therefore, if the LED light source is directly applied in a conventional light bulb without any modification, the light emission angle of the light bulb having the LED light source would be restricted, and particularly, the light intensity at a side opposite to the light-emitting side of the light source is even weaker. In order to increase the light emission angle of the lamp, some LED light bulbs are accessorized with a lampshade having the scattering effect. By such lampshade, the light intensity in the direction backward to the light-emitting side of the LED light bulb may be increased; however, it is still not enough to meet the requirement of the omnidirectional lighting, such as the Energy Star omnidirectional specification. That is, the Energy Star specifics that luminous intensity (cd) at any angle in the 0° to 135° zone shall not differ from the mean intensity for the entire 0° to 135° zone by more than 20%.